Osteoarthritis (OA) is the most common form
of arthritis. It develops when cartilage (the smooth covering over the
bones in your joints), starts to break down usually as a result of aging, trauma,
or increased wear and tear. As it worsens, OA can cause bone-on-bone friction.
There are several patterns of joint involvement in OA, most of which involve
only a few joints. The most common pattern involves the major weight-bearing
joints such as the hips, knees or lower spine. Most forms of OA become
symptomatic after age 50.

OA of the hands is a distinct subtype of OA,
and very common in women. This type of arthritis can often begin when
a woman is in her 20s or 30s. Unlike the gradual onset of other types
of OA, this type can begin suddenly and can be quite painful. It is
progressive and causes classic deformities of the fingers with enlarged joints.
Eventually, this condition runs its course and the pain subsides, but the deformities
remain.

OA should not be confused with "osteoporosis"
(weak or brittle bones which can lead to an increased risk of fracture), although
many women (especially those who have gone through menopause) may have both
of these conditions simultaneously. Certain types of arthritis-or medications
used to treat arthritis-may increase your risk of osteoporosis, so you should discuss this
with your physician.

OA is probably a disease of multifactorial
origin. Hereditary factors may be the most important, but in most patients
with OA a specific cause is never identified. Other things which may increase
your risk of getting OA or of worsening your existing OA include: being overweight,
chronic stress across joints, multiple microfractures in the related bone, major
joint trauma (think skiing accidents), or other metabolic or inflammatory injuries.
And yes, cracking your knuckles does increase your risk of arthritis of the
fingers. It is unknown whether there is a relationship between estrogen
(either in birth control pills or in hormone replacement therapy) and arthritis.
Because of the gender differences in OA and RA incidence, hormones have long
been suspected to have a role in disease origin and progression.
As a result, rheumatologists tend to avoid recommending oral contraceptives
and estrogen replacement therapy (ERT) for fear of causing the disease to worsen.
However, we know that certain arthritic conditions (such as RA) may go into
remission in pregnancy, during which hormone levels are very high.